Static link on Linux. And better document release process on OSX.

bitcoin-qt.pro

@@ -19,6 +19,17 @@ OBJECTS_DIR = build
 MOC_DIR = build
 UI_DIR = build
 
+# use: qmake "RELEASE=1"
+contains(RELEASE, 1) {
+    # Mac: compile for maximum compatibility (10.5, 32-bit)
+    macx:QMAKE_CXXFLAGS += -mmacosx-version-min=10.5 -arch i386 -isysroot /Developer/SDKs/MacOSX10.5.sdk
+
+    !windows:!macx {
+        # Linux: static link
+        LIBS += -Wl,-Bstatic
+    }
+}
+
 # use: qmake "USE_UPNP=1" ( enabled by default; default)
 #  or: qmake "USE_UPNP=0" (disabled by default)
 #  or: qmake "USE_UPNP=-" (not supported)
@@ -255,4 +266,11 @@ LIBS += $$join(BOOST_LIB_PATH,,-L,) $$join(BDB_LIB_PATH,,-L,) $$join(OPENSSL_LIB
 LIBS += -lssl -lcrypto -ldb_cxx$$BDB_LIB_SUFFIX
 LIBS += -lboost_system$$BOOST_LIB_SUFFIX -lboost_filesystem$$BOOST_LIB_SUFFIX -lboost_program_options$$BOOST_LIB_SUFFIX -lboost_thread$$BOOST_THREAD_LIB_SUFFIX
 
+contains(RELEASE, 1) {
+    !windows:!macx {
+        # Linux: turn dynamic linking back on for c/c++ runtime libraries
+        LIBS += -Wl,-Bdynamic
+    }
+}
+
 system($$QMAKE_LRELEASE -silent $$_PRO_FILE_)